1. Field of the Invention
This invention relates to devices for protecting pendant controls of the type used to remotely operate trolleys in mills, or other industrial or commercial buildings and the like.
2. Description of the Prior Art
Overhead devices for moving materials are found in many mills, such as steel mills, factories, warehouses, stores and other industrial and commercial buildings. These devices, known as trolleys, overhead cranes, or hoists, are usually remotely operated from floor level through the use of a pendant control or switch which is suspended from the trolley by cable and electrically connected to mechanism, including a motor, on the trolley which causes the trolley to move in a desired direction on overhead rails, the trolley to move up and down and/or the overhead bridge to move in and out.
Since the pendant control must be low enough for an operator to reach it, it is also likely to be struck by other objects on the mill or building floor, for example, mill products being moved by forklift trucks, or to swing and strike other objects such as inventoried products like bars, coils, cartons, or scrap materials as it is being moved from one position to another. Hence, some sort of device is needed to protect the pendant control from being damaged.
Furthermore, it is desirable that the pendant control be caged or substantially covered in some manner to prevent accidental operation of the pendant control, which might cause undesired movement of a trolley on the overhead rails, resulting in possible injury to persons or property on the mill or building floor or near the rails.
U.S. Pat. No. 2,791,665 discloses one device for protecting pendant switches. That device is a protective housing or sheath of rubber or other yieldable material which encapsulates a switch or switches. The sheath is provided with openings through which pushbuttons of the switch can be actuated to control an overhead crane. Not only is the sheath more elaborate than necessary, and therefore more expensive, but is has several deficiencies. In the first place, the protective housing or sheath cannot be removed from the switches without disconnecting the electrical leads from the switches. Second, the metal tubular casing which extends through the sheath around the switches has a constant diameter. Hence, the same sheath cannot be used for all sizes of pendant switch housings which are or may become available. Third, the switches must be located in a specific position within the sheath in order for the pushbuttons to be accessible. Consequently, it may not be possible to substitute a switch of a different size having different pushbutton locations in the same sheath.
The present invention overcomes all of these deficiencies. It is a simple, fabricated, relatively inexpensive pendant control protector which can be easily installed and removed without disconnecting the electrical connection to the control, and which can accommodate any size of pendant control presently available or likely to be used in the foreseeable future.
Other advantages will become apparent from a reading of the following description of the invention.